If I remember correctly, I played this game long time ago, after pushing him to the edge he will try to crush you and after that there should be a prompt to press a "button" (attack button) repeatedly.

To push him over the tapping has to be at the beginning at the rhythm on screen following a VERY fast tapping, I remember putting the controller on my knee and tapping with my index finger because this way I could tap faster. I had to do that more than once.

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If real is what you can feel, smell, taste and see, then 'real' is simply electrical signals interpreted by your brain

HERE you can see a video of how to kill him, the prompts are for PS3, equivalent prompts for PC should appear in your screen. Hope this helps, a lot of people have to do it more than once to get it perfect.

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If real is what you can feel, smell, taste and see, then 'real' is simply electrical signals interpreted by your brain